Device for putting a catheter tube into place in a vein

ABSTRACT

A device for installing a catheter tube in a vein by the Seldinger method, once the device has been inserted, has a tubular cylindrical sheath, with a slot running its entire length, mounted on a dilator tube. A cylindrical main portion of the sheath terminates at a distal end edge which flares forwardly and is adjacent a shoulder of the dilator tube for enabling the dilator tube to be withdrawn through the sheath.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a device having a tubular sheath associatedwith a “dilator” tube for putting a catheter tube into place in a veinafter the device has been inserted by the “Seldinger” method.

2. Background of the Invention

This sildinger method requires the following operations:

1) puncturing the vein with a needle;

2) inserting a metal guide into the vein through the puncturing needle;

3) withdrawing the needle;

4) inserting an assembly constituted by a sheath threaded on a dilatortube over the metal guide;

5) withdrawing the dilator and the guide, leaving the sheath in place;

6) inserting the catheter in the sheath; and

7) withdrawing the sheath.

A problem arises in facilitating insertion of the sheath in the body andextracting it therefrom while reducing the risk of trauma.

Various solutions to that problem are described in the followingpublications: U.S. Pat. No. 5,499,975, U.S. Pat. No. 5,098,393, WO99/21605, and EP 0 792 660.

Furthermore, publication FR-A-2 439 591 describes such a tubular sheath(5) which has a resilient slot (6) along its entire length, the distalend (7) thereof being blunted and which is threaded onto a dilator tube(1) whose distal end (3) is tapering.

The term “resilient slot” means that the lips of the slot can move apartfrom each other, but return towards each other when the cause of theirmoving apart has ceased.

To make it easier to pass through the skin and through the vein wall,the distal ends of the dilator and of the sheath are subjected totreatment:

the dilator tapers so as to obtain a slope whose distal end is as closeas possible to the diameter of the guide; and

the sheath is made blunt so as to match the outside diameter of thedilator.

FIG. 1 of the accompanying drawings reproduces FIG. 1 of thatpublication, the sheath and the dilator being shown separately, whileFIG. 2 of the drawings reproduces FIG. 2 of that publication, the sheathbeing shown threaded on the dilator.

Making the sheath blunt is a difficult operation.

It is necessary to conserve a distal flat (step) to prevent the sheathturning inside-out on passing through tissue.

The sensation of an abutment thus remains as it passes through tissueand the vein, and this gives rise to trauma.

SUMMARY OF THE INVENTION

The present invention seeks to remedy those drawbacks.

According to the invention, this is achieved with a device whichcomprises a sheath having a cylindrical main portion and which is splitover its entire length by a resilient slot, said sheath being threadedonto a dilator tube which has a cylindrical main portion and a taperingdistal end, and which presents the following features:

the distal end of the tube connects with the main portion of the tubevia a shoulder that projects relative to said main portion;

the cylindrical main portion of the sheath terminates at a distal endedge which flares forwardly; and

the shoulder of the tube fits closely to the distal end edge of thesheath.

By means of this combination of characteristics, the tissues are passedthrough without coming into abutment and thus without trauma.

When the dilator is withdrawn, the slot of the sheath opens to allow theshoulder of the dilator to pass and then returns to its initial (closed)shape after the dilator has been fully withdrawn.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the invention is described below with reference to thefigures of the accompanying drawings, in which:

FIGS. 1 and 2, described above, reproduce FIGS. 1 and 2 respectively ofthe above-cited publication;

FIG. 3 is an axial section of an embodiment of a device having a sheathand a dilator of the present invention;

FIG. 4 is an elevation view (FIG. 4A) and a section view (FIG. 4B) ofthe distal ends of the sheath and the dilator of the device of theinvention;

FIGS. 5 and 6 are views on a larger scale respectively of the elevationand the section of FIG. 4; and

FIG. 7 is an elevation view corresponding to that of FIG. 5, but duringwithdrawal of the dilator.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The device shown in FIGS. 3 to 6 comprises:

a cylindrical tubular sheath (11) that is longitudinally split at (12)over its entire length and that is provided at its proximal end (i.e.the end that remains closer to the manipulator) with a handle (13) formaking it easier to grasp. The sheath is made in conventional manner outof a material enabling the slot to open under the effect of an elementof outside diameter larger than the inside diameter of the sheathpassing along the inside of the sheath, and to close up again on its ownafter said element has been withdrawn, thus providing that which isreferred to above as a “resilient slot”; for example, the sheath can bea polyurethane tube whose inside and outside diameters lie in the range1.5 mm to 5.5 mm; and

a cylindrical dilator tube (14) provided with a proximal coupling socket(15) and having a distal end (16) that tapers. This tube is made ofsynthetic resin, e.g. polypropylene.

In accordance with the invention, the distal end (16) of the dilatortube is connected to the main cylindrical portion (14) of the tube via ashoulder (17) that projects relative to said main portion.

The shape of this shoulder can be arbitrary but it is preferably given afrustoconical shape whose right section decreases from the front towardsthe rear, as in the example shown.

The end edge (18) of the distal end of the sheath (11) is frustoconicalin shape, flaring towards the front in a manner that corresponds to theshape of the shoulder so as to fit closely thereto.

The outside diameter of the main proton of the tube (14) is selected tobe substantially equal to the inside diameter (d1) of the sheath (11) sothat the sheath is engaged on the tube with a certain amount of frictionwhile the diameter (d2) of the tube at the greatest diameter of theshoulder is selected to be equal to or slightly greater than the outsidediameter (d3) of the sheath so that the sheath does not project outwardsat the shoulder.

What is claimed and desired to be secured by letters patent of theunited states is:
 1. A device comprising a tubular sheath and a dilatortube for installing a catheter tube in a vein by the Seldinger methodonce the device has been inserted, said sheath presenting a cylindricalmain portion (11) and presenting over its entire length a resilient slot(12), said sheath being mounted on a tube which presents a cylindricalmain portion (14) and whose distal end (16) tapers, the device havingthe following features: the distal end of the tube connects with themain portion of the tube via a shoulder (17) that projects relative tosaid main portion; the cylindrical main portion (14) of the sheathterminates at a distal end edge (18) which flares forwardly; and theshoulder (17) of the tube fits closely to the distal end edge (18) ofthe sheath.
 2. A device according to claim 1, in which the distal endedge (18) of the sheath is frustoconical in shape.
 3. A device accordingto claim 1, in which the outside diameter of the cylindrical mainportion (14) of the tube is substantially equal to the inside diameter(d1) of the sheath so that the sheath is engaged on the tube with acertain amount of friction, while the diameter (d2) of the tube at themaximum diameter portion of the shoulder is equal to or slightly greaterthan the outside diameter (d3) of the sheath so that the sheath does notproject outwards from the shoulder.
 4. A device according to claim 1, inwhich the sheath is provided at its proximal end with a handle (13).